Plaster composition.



UNITED STATES PATENT osrron CARLETON ELLIS, OF LARGHMONT, NEW YORK,ASSIGNOR 'IO ELLIS-FOSTER COMPANY,

A. CORPORATION OF NEW JERSEY.

PLASTEB COMPOSITION.

No Drawing.

Spedification of Letters Patent.

Application filed April 12, 1909. Serial No. 489,353.

Patented Apr. 26, 1910.

To all whom it may concern:

Be it known that I, OARLETON ELLIS, citizen of the United States,residing at Larchmont, in the county of Westchester and State of NewYork, have invented certain new and useful Improvements in PlasterComposl tion, of which the following is a speclfication.

This invention relates to a composition intended for plastering of wallsand similar purposes and relates particularly to a compositioncontaining calcined sulfate of lime and boracic material.

In the manufacture of borax from the calcareous material constitutingthe supply of the raw material, a refuse body is obtained consistinglargely of sulfate of lime and carrying 2% to 3% anhydrous boracim acidcombined more or less with lime, etc. I have found that this materialmay be calcined to remove the water of hydration of calcium sulfate andin a measure to dehydrate the boracic material so as to produce acomposition setting quickly to a hard cementitious mass on admlxturewith water.

While the sulfate sludge varies more or less in composition, arepresentative analysis is the fo lowing :-lime, 37.28%; sulfuric acidanh drous,'51.40%; silica, 4.48%; anhydrous ric acid, 2.10%; magnesia,24%) water, 2.19%. These figures are reckoned on the material in asubstantially anhydrous condition.

Prior to dehydration, the calcium sulfate has in combination with it twomolecules of water to 1 molecule of calcium sulfate and this should belargel removedby calcinati on. This is efi'ecte by heating'the mater1alin kettles with agitation to a temperature of about 360 F. although bycareful stlrring a temperature of 400 or more ma be attalned withoutimpairment of the pro uct. By this heat treatment, the water of hdration is largely eliminated and the calclum sulfate in its dehydratedform and in the presence of boracic material, has marked settingqualities and roduces a laster setting to a very-desira le degree 0hardness. The presence of boracic material tends to prevent shrmking andcracking and overcomes to some extent the brittleness observable mplaster of paris which has been allowed to set.

Calcination may be conducted in a con tinuous manner in a'rotary kilnfor example.

By heatin to temperatures of say 900 or 1000 F. t ecomposition loses theproperty of rapid setting. The material thus calcined may be c mbinedwith a quantity of filling and extending materials and a suitableformula consists of calcined sulfate Waste 10 parts, sand 20 parts,short fibered asbestos 2 parts, wood fiber 2 parts. Another formulaconsists of calcined sulfate waste 10 parts, hydrated lime 7 parts, woodfiber 2 parts, hair 1 part, sand 15 parts. Suitable retarders such asglue may be added to modify the rate ofsettmg.

Other filling and extending materials may of course be introduced 'asfor example, serpentine, asbestine, powdered talc, clay, zinc oxid andvarious coloring bodies such as iron oxid, ultramarine, Guignets green,and the like.

In using this material, sufiiclent water is added to make a plastic massand this is I troweled on the wall in the usual manner.

The proportion of sand or other filling material may be varied so as toproduce the various effects and qualities desired in the scratch coat,brown coat, finishing coat, etc., according to the circumstances.

Having described my invention to the details of which I do not wish tolimit myself, what I claim is 1. A cement material comprising limesulfate borax waste calcined to remove water of hydration.

2. A plaster com osition comprising calcined lime sulfate orax waste,filling and extendin materials.

3. A p aster composition comprising calcined lime sulfate borax waste,fibrous material and-extending material.

4. A plaster composition comprising calcined lime sulfate borax Waste,fibrous material and sand.

5. A plaster composition comprising calcined lime sulfate borax waste,fibrous material, sand and hydrated lime.

6. A laster composition comprising lime sulfate orax waste, calcined ata temperature not exceedingl400 F.

In testimony w signature in presence of two witnesses.

' Witnesses:

NATHANIEL L. Fos'rna, FRANCES I. NEWMAN.

ereof I have afiixed my,

CARLETON ELLIS.

